WASHINGTON  Solar power, still a tiny fraction of the energy used today, may be heading closer to the mainstream -- if a display on the National Mall over the past week is any indication.

Twenty universities brought solar homes to Washington, assembled them in the shadow of the Washington Monument and became a weeklong magnet for people wanting to see what these technology-filled homes were all about. To many visitors, they no longer looked like oddball experiments, but dwellings that had the look and feel -- although smaller -- of houses in suburbia.

Even storm clouds and drizzle didn't keep the curious from standing in long lines one afternoon to look at the one-bedroom homes that had been assembled by students from 16 states, Puerto Rico and three foreign countries.

As the rain fell, batteries hidden beneath attached decks and porches provided the juice from energy that had been absorbed on sunny days.

Judges ranked each of the houses on 10 criteria, from architecture to market viability to engineering to livability. They required students to wash clothes, prepare meals, run a television, maintain comfortable temperatures and even use excess power to drive a plug-in electric car -- and finish the week having used no more electricity than the sun provided.

A team of students from Germany's Technische Universitat Darmstadt won the weeklong competition as judges concluded their box-like dwelling was the most efficient, well-designed and well-engineered home in the competition. It featured three walls of solar cell-imbedded louvers that were adjusted automatically by a computer to best take advantage of the sun.

The German design "pushed the envelope on all levels," Energy Secretary Samuel Bodman said in announcing the winner Friday, calling it "the house people have been lining up all week to watch."

A team from the University of Maryland finished second. Visitors touring their house were attracted by an indoor waterfall that provided a novel way to use a liquid desiccant to soak up humidity so less energy was needed for cooling.

"The concept is sound," said Brian Borak, 25, a chemistry major, adding that it's been used in industrial applications, but never in a residential situation. The university is thinking of filing a patent.

Renewable energy sources -- mostly wind turbines -- account for a little more than 2 percent of electricity production. A very small percentage comes from solar, or photovoltaic, cells such as those used in the houses on the Mall, according the Energy Department.

But in the two years since the last Solar Decathlon, the competing house designs have become more mainstream, according to judges and participants. For the first time a category of "market appeal" was added to the criteria on which teams were judged. While the prototype homes were said to cost $500,000 or more to design, ship and erect, they also contained many features that are commercially available, according to competition organizers.

"In 2005 (the houses) were experiments. This year they're not. ... They're an example of what can be done," said Bob Burt, a building consultant who was one of the judges ranking the homes on market appeal. "There are a couple of houses that when I first walked in I said, 'Yeah, I could live here.'"

Leo and Darlene Michitsch, visiting from Cleveland, saw in the homes not only a glimpse into the future, but also a hint of something here today.

"We have an interest in putting improvements into our home," said Darlene, who teaches art at a university. The couple had already visited several of the houses and "we're learning a lot," she said.

Lori Johnson, of Lakewood, Colo., said the modernistic design of most of the houses "is not my style" but they had piqued her interest in solar.

"We've talked about the idea of (using) more solar in our home," she said, noting that Colorado had ideal conditions for the technology.

"These houses, generally speaking, are much more real, much more part of the next generation of something that is actually going to be built," said Bodman, the energy secretary, whose department sponsored the competition.

The winning German entry was cited not only for its solar technology and energy saving, but for its efficient use of space and multifunction design. Its solar cell-imbedded louvers were a source of both shade and energy. The furniture was made so it could be lowered and hidden beneath the floor when not in use to make rooms multifunctional.

The large crowds and high level of interest surprised many of the students. "We're also surprised that they like our strange ideas," said Andreas Pilot, 28, an architect student and member of the German team.

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People view the solar house built by the team from Technische Universitat Darmstadt after it was announced that they won the 2007 Solar Decathalon, Friday, Oct. 19, 2007, in Washington. The Washington Monument is at left. (AP Photos/Susan Walsh)